Microsoft Windows provides a control used to select
dates on a colorful calendar:

The dates used and the way they display are based on the
Regional Settings of the Control Panel. It may also depend on the operating
system. This convenient control is called a month calendar or simply a
calendar. The title bar of the control displays two buttons and one label.
The left button allows the user to select the previous value depending on
the type that is displaying on the label (month, year, decade, or century).
The user does this by clicking the left button. By default, the label
displays the currently selected month and the year. The right button is used
to get to the next value (month, year, decade, or century, depending on the
value on the label).

Under the title bar, the short names of week days
display, using the format set in the Windows Control Panel. In US English,
the first day is usually Sun for Sunday. The first day can be changed by the
programmer. On the control, the currently selected date is highlighted. In
the main area, the numeric days of the month display on a white background
(this color and any color on the control can be changed). To select a date,
the user can click it in the list.

By default, the calendar opens with today's day
highlighted. Using the buttons of the title bar, the month-year label, the
user can change the date. If at one time the month calendar is displaying a
date other than today, and if the user wants to return to today's date, he
or she can:

Click the bottom label that displays Today (you as the programmer
can hide the Today label if you want)

Right-click anywhere on the control and click Go To Today

If the month calendar displays regularly (with a month,
a year, the week days, and the days of a month), if the user clicks the
label that is between the buttons, the month calendar displays a list of 12
months from January to December, and the month of the date that was
previously selected is highlighted. Here is an example:

If the month calendar is displaying a list of months:

To select a month, the user can click it

To get the 12 months of the previous year, the user can click the
left button

To get the 12 months of the next year, the user can click the right
button

If the month calendar is displaying the names of months
and if the user clicks the year, the label would display a decade of the
current year and the 9th year from it. The body of the month calendar would
display the years in that decade, plus the year prior to that decade and the
year after that decade:

That display has new options:

To select a year, the user can click it

To get a list of the previous 12 years, the user can click the left
button

To get a list of the next 12 years, the user can click the right
button

If the month calendar is displaying the numbers of 12
years and if the user clicks the label, the label would display a century
from the current year and the 99th year from it. The body of the month
calendar would display 12 labels that each shows a decade:

This time:

To select a decade, the user can click it

To get a list of the previous decades, the user can click the left
button

To get a list of the next decades, the user can click the right
button

The calendar can be configured to display more than one
month. You have many options. You can display the months horizontally:

Or you can display them vertically:

If the control is displaying more than one month, the
buttons would increment or decrement by the previous or next value (month,
year, decade, or century) in the list. For example, if the control is
displaying April and May and if the user clicks the left button, the control
would display March and April. If the control is displaying April and May
and if the user clicks the right button, the control would display May and
June.

The month calendar control is based on the
MonthCalendar class, which is based on the Control class. To
visually create a month calendar control, you can click the MonthCalendar
button
in the Toolbox and click the form or the desired container. To
programmatically create a month calendar, declare a variable or type
MonthCalendar and add it to the Controls collection of its container.
Here is an example:

A month calendar is primarily a Windows control. It gets
it primary properties from the Control class. Based on
this, when creating it, you can specify its location, its size, and other
characteristics.

When the user clicks the month calendar, one date is
selected. As mentioned in our description, you can give the control the
ability to display more than one month. To make this possible, when visually
creating the control, set its width to have enough space. In the same way,
you can increase the height to display many months. This allows you to
display as many months as you judge necessary. Here is an example:

To make it a highly visual object, the month calendar
uses different colors to represent the background, week days, the background
of the title bar, the text of the title bar, the text of the days of the
previous month, and the text of the days of the next month. To visually
control the colors, access the Properties window for the month calendar.

Application:
Enlarging a Month Calendar

On the form, click the mon calendar control

Drag its right border so it can display two months:

Execute the application and try selecting a range of dates

Close the form and return to your programming environment

Selecting a Date

As mentioned in our description, the calendar control
displays the days of a selected month. The control also displays the
remaining days, if any, of the first week of the currently selected month;
that is, the days of the previous month that share the week with the first
day of the first week of the selected month. The control also displays the
first days of the subsequent month that share the week with the last day of
the current month.

To use the calendar control, the user can click a date,
whether it a date from the current month or a day of the other (previous and
next) month. When the user has clicked a date to select it, the control
fires a DateSelected event. The DateSelected event is of type
DateRangeEventArgs.

The user can also select a date using the keyboard. To
do this, the user must first give focus to the control. This is possible by
pressing Tab continuously until the control receives focus (or by clicking
any date on the control). To select a date using the keyboard, the user can
continually press one of the arrow keys (on the keyboard) until the desired
date is selected.

You too can programmatically select a date on the
calendar control. To do this, assign a valid DateTime value to both
the SelectionStart and the SelectionEnd properties. Here is an
example:

When a date has been selected, whether by the user
(using the mouse or the keyboard) or by you (through code), the control
fires a DateChanged event. The DateChanged event is of type
DateRangeEventArgs.

The DateRangeEventArgs class is equipped with two
properties: Start and End. When the user clicks a date, these
two properties hold the date that was clicked. This means that you can use
either of these properties to know the date that was clicked. Both the
Start and the End properties are of type DateTime.

Application:
Selecting a Date

On the form, click the month calendar

In the Properties window, click the Events button and double-click
DateSelected

When the user clicks the calendar control, one date is
selected. As mentioned in our description, you can give the control the
ability to display more than one month. To make this possible, when creating
the control, set its width to have enough space. In the same way, you can
increase the height to display many months.

To select more than one date, the user can click one
date, hold the mouse down, and drag to the left, the right, up or down:

The user can also select a range of dates using the
keyboard or using a combination of the mouse and the keyboard. To do this,
the user must first give focus to the control. To select a range of dates
using the keyboard, the user can press and hold Shift, then press one of the
arrow keys continually until the last date of the desired range is
selected (in reality, we will see that there is a property that controls the
maximum range of dates that can be selected). To select a range of dates
using a combination of the mouse and keyboard, the user can click the first
date, press and hold Shift, then click the last date.

After selecting the days, the starting date is stored in
the SelectionStart property. The last date of the selection is stored
in the SelectionEnd property. Both properties are of DateTime
type. The range of the selected dates is stored in a SelectionRange
value. SelectionRange is simply a class that can give you information
about the beginning and the end of a selected range of dates.

To programmatically select a date, assign the starting
to the SelectionStart property and assign the last date to the
SelectionEnd property.

By default, the user can select only up to 7 days at a
time. If you want, you can let the user be able to select more or less days
than that. If you configure the control to display more than one month, the
user can select days from one month to another as long as the days are in a
range.

After selecting a range of dates, the control fires a
DateChanged event, which is of type DateRangeEventArgs. We saw
earlier that the DateRangeEventArgs class has two properties. The
DateRangeEventArgs.Start property holds the starting date of the range
that the user made. The DateRangeEventArgs.End holds the last date
from the range that the user made.

The Maximum Date Range Selection

To control the number of days you want the user to be
able to select, change the value of the MaxSelectionCount property.
The user cannot select more days than the MaxSelectionCount value but
the user can select less.

The calendar control is a rectangular object without a
border. After placing it on the form, it displays the current month and only
one month. This is because, by default, its width and height are set enough
to accommodate only one month.

To make it a highly visual object, a month calendar
control uses different colors to represent the background, week days, the
background of the title bar, the text of the title bar, the text of the days
of the previous month, and the text of the days of the next month.

To visually change a color, you can click its field in
the Properties window, and:

Click the arrow of the combo box to select from one of the tabs

Type the name of the desired color. The color name must be standard

Type the R-G-B value as 0-255, 0-255, 0-255

To programmatically change a color, access its property
name in code and assign the desired , whether by name or using its RGB
value.

The Background Color of the Title Bar

As mentioned already, the top section of the calendar
control displays buttons and labels. By default, these are positioned on top
of a blue background. The background color of this section is controlled by
the TitleBackColor property. Here is an example of changing it:

By default, the labels on the title bar display in a
white color defined by the ActiveCaptionText system color. The color
used to paint the text of the labels of the title bar is controlled by the
TitleForeColor property. Here is an example of changing it:

As mentioned already, to change month and subsequently
the year of the calendar, the user can click the buttons continuously. By
default, the user can navigate from 1/1/1753 to 12/31/9998. If you want to
limit the allowable dates beyond which the user should not navigate, use the
MinDate and the MaxDate properties.

The First Day of the Week

Under the title bar, the short names weekdays display,
using the format set in Control Panel. In US English, the first day is
usually Sunday. If you want to start with a different day, set the value
using the FirstDayOfWeek property. The names of weekdays use the same
color as the TitleBackColor property. Under the names of the week,
there is a horizontal line used as the separator. By default, this line
separator is painted in black but it uses the same color as the numeric
values of the days of the selected month.

The Background Color of the Calendar

Under the line separator, the numeric days of
the month are listed. By default, the numeric days of the control
display above a white background which is the Window system
color. This color is controlled by the overridden BackColor
property.

The Font Color of the Days of the Current Month

The numbers of the days of the month display in two colors. The
real days of the selected month display, by default, in a black
color as the WindowText system color. The color of these days
is controlled by the overridden ForeColor property.

The Font Color of the Days of the Trailing
Months

Besides the days of the currently selected month, the
calendar control also displays one or more days of the previous month and
one or more days of the subsequent month. These are referred to as trailing
months or trailing days. These are dayts that don't belong to the currently
selected month. These days display in a different color controlled by the
TrailingForeColor property. By default, this color is set to GrayText:

Of course, you can programmatically change these colors.
Although any color is allowed in any category, you should make sure that the
calendar is still reasonably appealing and usable.

Showing Today

The calendar control is used to let the user know
today's date in two ways. On the calendar, today's date is circled by an
almost hand-drawn ellipse. In the bottom section of the calendar, today's
date is also displayed as a sentence. If you want to display or hide the
bottom label, set the ShowToday Boolean property accordingly. For
example, to hide it, set this property to false. The presence or absence of
this ellipse is controlled by the ShowTodayCircle Boolean property
whose default value is True. If you set this property to False,
today's would appear without the ellipse:

When a new calendar control is added to an application,
it assumes today's date. If you want to change this date, use the
TodayDate property.

Bold Dates

To accentuate the importance of one or more days of a
month, you can bold some days. To bold some days of the month calendar,
create an array that holds the days. To visually create the list of dates,
on the form, click the calendar control. In the Properties window, click
BoldDates and click the ellipsis of its field. This would open the DateTime
Collection Editor. To add a date member, you can click Add. On the right
side, there would be a field named Date. You can type the date or you can
click the arrow of the field. This would display a calendar:

You can then select a date. In the same way, to complete
the array, you can create the other dates you want. After creating the list,
you can click OK.

To programmatically create the list of dates, create an
array of DateTime values (each member of the array must be a recognizable
DateTime value). Once the array is ready, assign it to the BoldDates
property.

If you prefer the months bolded, assign the array to the
MonthlyBoldedDates property.